Construction toys with dimple-containing magnet
Kind Code:

A containing a dimple the face the magnet and construction toys utilizing dimple-containing magnets and ferromagnetic spheres or dimple-containing ferromagnetic structures and magnetic spheres and other components.

Roger, Scott Thomas (Ottawa, CA)
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Publication Date:
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International Classes:
A63H33/04; (IPC1-7): A63H33/26
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Primary Examiner:
Attorney, Agent or Firm:
Lee Valley Tools / Kilpatrick Townsend & Stockton (Atlanta, GA, US)
1. A construction toy component comprising a magnet having a dimple.

2. The construction toy component of claim 1, further comprising a plastic part connected to the magnet.

3. The construction toy component of claim 2, wherein the plastic part comprises a spar.

4. The construction toy component of claim 2, further comprising a second magnet having a dimple and connected to the component.

5. The construction toy component of claim 3, further comprising at least another magnet having a dimple and connected to the spar.

6. A construction toy kit comprising a ferromagnetic sphere and a magnet having a dimple encircled by a dimple rim for contact between the sphere and the magnet at least along the dimple rim.

7. The construction toy kit of claim 6, wherein the sphere has a first radius and the dimple surface that is not spherical.

8. The construction toy kit of claim 7, wherein the dimple surface is a truncated cone.

9. The construction toy kit of claim 8, further comprising a plastic part attached to the magnet.

10. The construction toy kit of claim 9, wherein the plastic part comprises a spar.

11. A toy comprising: (a) a plastic part connected to a ferromagnetic part containing a dimple and (b) a ferromagnetic sphere, wherein one of the sphere or the dimple-containing part are magnetized.

12. A construction toy part comprising a spar having two ends and, positioned in each end, one magnet having at least one dimple.

13. A construction toy comprising: (a) a plurality of plastic spars, each containing at least one dimple-containing magnet, and (b) a plurality of spheres positionable in the dimples.

14. A kit comprising: (a) a plurality of plastic parts, each containing at least two dimple-containing magnet, (b) a plurality of spheres positionable in contact with the magnets at the dimples, (c) a plurality of ferromagnetic rings, (d) at least one ferromagnetic base.

15. The kit of claim 14 wherein the at least one ferromagnetic base comprises a plurality of disks.

16. The kit of claim 15, wherein the at least one ferromagnetic base is a disk and at least one of the plastic parts contains at least three dimple-containing magnets.



This application claims priority to U.S. Provisional Patent Application Ser. No. 60/512,952 filed Oct. 21, 2003 entitled “Dimple Containing Magnet” which is incorporated herein by reference.


This invention relates to magnets and, in particular, to toys and toy construction sets utilizing magnets.


Magnets exhibit such interesting properties and permit such easy “construction” of structures containing them that they have long been used as toys and have long been incorporated in toys. The relatively recent availability of inexpensive, extremely strong rare earth magnets has enabled design of improved toy magnets and toys containing magnets. Among such toys are building components including steel spheres or spherical magnets and “spars,” elongated structures containing magnets in their ends for magnetic attachment to other such spars or other structures such as spheres.

Contact between a sphere and a conventional flat magnet surface is a point contact that provides essentially no lateral stability. As a result, construction toy spars that have flat-end magnets exhibit no lateral stability when magnetically connected to a spherical surface, therefore often requiring additional spars for lateral support. FIG. 1 is a side view of an end of a spar 8 holding a flat-end magnet 10 contacting a sphere 12 in such a prior art structure that achieves one-point contact. FIG. 2 illustrates another prior art structure in which a spar 8 holds a flat-end magnet 14 penetrated by a small hole 16 so that contact with a sphere 12 will be between the spherical surface and the rim 18 of the spar magnet 14 hole 16.

However, since a magnet's performance (other factors being equal) is a function of its geometry and volume, such magnets penetrated by a hole sacrifice function. A through hole in the face of a magnet results in an air path through the magnet, which reduces its magnetic power, and a hole removes magnet material, which also reduces magnetic power. These considerations cause it to be desirable to use a smaller hole, but the smaller the hole (and therefore the smaller the diameter of the rim that contacts a steel sphere) results in reduced lateral stability and reduced strength. In addition, a small through hole traps contaminants such as oils and grease during the manufacturing process that are difficult to remove by conventional means. Furthermore, if not removed, these contaminants migrate out of the hole in the magnet during the application of a protective coating (such as nickel plating) resulting in poor adhesion of the protective coating, which then flakes off. Without a protective coating a rare earth magnet will corrode or rust, which reduces the magnet's performance.


A dimple in the face of a magnet, such as a magnet affixed to a spar end, provides a strong, laterally stable magnetic connection with a sphere, particularly if the rim or intersection between the surface of the recess and the face of the magnet is a circle. Such a dimple or recess, as compared to a hole through an otherwise comparable magnet, provides greater magnetic strength by eliminating the air path through the magnet and by avoiding significant loss of magnetic material to the hole and is easily cleaned of contaminants.


FIG. 1 is a side view of a prior art flat end magnet contacting a sphere.

FIG. 2 is a side view similar to FIG. 1 but showing a flat end magnet with a through hole contacting a sphere.

FIG. 3 is a side view of a dimple-containing magnet of this invention positioned near a sphere.

FIG. 4, is another view of the dimple-containing magnet of this invention shown in FIG. 3 positioned near a larger diameter sphere.

FIG. 5 is a side view of a construction toy spar containing two dimple-containing magnets of this invention and a sphere of the same radius as the dimple.

FIG. 6 is an alternative embodiment of the dimple-containing magnet of this invention having a dimple that is not defined by a spherical surface.

FIG. 7 is a Y-connector construction toy component of this invention.

FIG. 8 is an X-connector construction toy component of this invention.

FIG. 9 is an illustrative assembly of construction toy components of this invention.


FIGS. 3-6 illustrate alternative embodiments of the dimple-containing magnet of this invention, shown mounted in another object, which may be a toy component such as a construction toy spar or any other component desired.

FIG. 3 illustrates a dimple 20 in a magnet 22 in a toy component 24 positioned near a sphere having a radius comparable to the radius of the dimple. FIG. 4 shows a like spar 24 and magnet 22 but having a dimple 26 with a smaller radius “r” than the radius “R” of a sphere 28.

FIG. 5 illustrates that by forming a dimple 34 as a concave surface 35 with a radius “r” exactly matching the radius “r” of the surface 36 of a steel sphere 38 with which the dimple-containing magnet is used, contact will be achieved across the entire dimple 34, providing substantial lateral support and maximizing the magnetic connection. If, on the other hand, a dimple is defined by a semi-spherical surface having a slightly shorter radius than the radius of the steel sphere, then contact will occur between the two at the rim of the magnet dimple, thereby maximizing lateral stability. Such a dimple having a slightly shorter radius semi-spherical surface ensures highly stable contact with spheres of approximately the same size while not requiring exact identity of sphere size from one sphere to another. Ring contact also ensures minor defects (protrusions) on the sphere do not significantly affect performance as would be the case for exactly matching magnet dimple and sphere radii, which could result in point contact verses ring contact. FIG. 5 further illustrates this invention in a magnet 22 having a dimple 34 that fully occupies the end 23 of the magnet 22, thereby providing the largest dimple area possible for this magnet.

In FIG. 5, the radius r of the dimple is equal to the radius r of the sphere 36, theoretically enabling contact between the entire dimple surface 35 and the surface 38 of the sphere 36.

A somewhat exaggerated-for-clarity example of a smaller radius dimple 26 and larger sphere 28 is illustrated in FIG. 4, where the magnet 22 dimple 26 has a shorter radius r than the longer radius R of the sphere 28. As may be seen in FIG. 4, a portion of the surface 30 of the sphere 28 is received within the dimple 26, but there is contact between the sphere surface 30 and the magnet only at the rim 32 of the dimple 26.

Incorporation of such dimples in the ends of magnets removes relatively little magnetic material and avoids the pole-to-pole air path introduced by a through hole as illustrated in FIG. 2.

As will be readily appreciated by study of the figures and consideration of the information set forth above, dimples usable to obtain the benefits of this invention can have shapes other than the semi-spherical shapes illustrated in the accompanying figures and described above, although the semi-spherical shape will typically be optimal. For instance, the dimple could have a shape of the inside of a cone or a truncated cone like the truncated conical shape 50 of the dimple 52 illustrated in FIG. 6. Numerous other shapes would likewise be possible, provided that there are at least three reasonably separated points of contact between the sphere and the magnet. For instance, a dimple having a shell-like series of scallops would provide a series of peripheral contacts establishing a stable magnet to sphere connection. As should likewise be appreciated, while most of the discussion above assumes that the spar end will be a magnet and the sphere simple steel, the components could be reversed by using a spherical magnet and a ferrous metal spar or spar end.

As will also be apparent to those skilled in the art of magnet manufacture, the dimples of this invention can be formed in magnets or ferrous metal structures by a variety of methods including conventional machining and metal-forming methods.

Spars or other parts containing magnets with dimples can contain one dimple-containing magnet 22, as illustrated in FIG. 3, two magnets 22, as illustrated in FIG. 5, three magnets 22 as illustrated in FIG. 7 showing a Y-connector 60, four magnets 22 as illustrated in FIG. 8 showing an X-connector 70. Other numbers of dimple-containing magnets are also possible.

Components containing dimple-containing magnets in accordance with this invention can be assembled in an endless variety of ways with numerous other ferromagnetic or ferromagnetic-containing components. For instance, such components can be assembled as shown in FIG. 9 with spars 24 resting on disks 29 and supporting spheres 28 that in turn hold spars 25 that contact spheres 28 at one of their ends and a ring 31 at the other of their ends.

These and other variations of this invention are all within the spirit and scope of this invention, the foregoing description and accompanying drawings, and the following claims.

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